91av

ELVIS is still alive, say a pair of respected cosmologists. Not only that but
Marilyn Monroe came up with the theory of relativity, the dinosaurs survived and
went on to invent the automobile and Al Gore, not George Bush, is the US
President. “In fact, as long as a history is consistent with the laws of
physics, it will not only happen but happen an infinite number of times,” says
Alexander Vilenkin of Tufts University in Medford, Massachusetts.

It seems far-fetched but Vilenkin and Jaume Garriga of the Independent
University of Barcelona say it’s just a logical consequence of
“inflation”—the most widely accepted model of the Universe’s birth.
Inflation says the early Universe expanded extremely rapidly. This expansion was
so fast, the researchers believe, that distant regions of the Universe have been
entirely isolated from each other ever since, because light hasn’t had time to
travel between them.

Because of the inherent randomness involved in the formation of stars and
galaxies, each of these “O-regions” should develop differently—and have a
different history. Because inflation also predicts that the Universe is
infinite, this means there are an infinite number of O-regions too. But Vilenkin
and Garriga wondered if the number of possible histories is also infinite.

They reasoned that you cannot examine a particular O-region in infinitely
fine detail. There is a quantum “blurriness” to space that makes it impossible
to tell apart histories that are very similar to each other. “We calculate that
there cannot be more than 10 to the power of 10¹⁵⁰ distinct histories,” says
Vilenkin. “It’s a fantastically huge number but it isn’t infinite.”

So, if there are an infinite number of O-regions but a finite number of
histories, every possible version of history will occur, and it will occur an
infinite number of times. “Not only is Elvis still alive but an infinite number
of Elvises are still alive,” says Vilenkin.

Vilenkin admits that this might cause people to take a fatalist view of
existence. Although there may be O-regions where tax does not exist, there may
be others where Hitler won the Second World War or the Cuban missile crisis led
to global annihilation. “I find the idea that all bad things happen very
depressing I admit,” says Vilenkin.

Alan Guth of the Massachusetts Institute of Technology, the “father” of
inflation, doesn’t offer any get-out. “I don’t see any weaknesses or flaws in
the work,” he says. So if inflation is correct—and several experiments
recently gave it strong support
(91av, 5 May, p 6)
—the worst may
already have happened somewhere out there. And, as light continues to travel
further and further, O-regions will continue to grow and increasingly to
overlap.